Flexible-bladed fan



. Aug.; 26, 1941. L. ZAIGER 2 FLEXIBLELBLADED FAN Filed Aug. 5, 19323 5Fig-2.

entor Louis cliger WWW An I ya.

Patented Aug. 26, 1941 UNITED STATES PATENT orrrce FLEXIBLE-BLADED- FANLouis Zaigfer, Lynn, Mass.

. Application August 5, 1938,.'Serial No-. '22 3,24=1

9' Claims.

vide a fan of this type in which each blade is interiorly reinforced.150 such an extent as. to

give it sufficient rigidity to maintain its pitch angle, the interiorreinforcement being of such character that it does not interfere with.the flexible character of the blade.

In a fan embodying my invention, the reinforced blades are preformed togive them the required curved shape and pitch angle and then are securedto the exterior of the hollow hub member by a connection which, ofitself, would not produce the required curved shape of and pitch anglein the blade, such curved shape angle being maintained by the interiorreinforcement of the blade.

Other objects of the invention are to. provide various improvements. inflexible-bladed fans which will be more fully hereafter set forth.

In the drawing wherein I have illustrated som selected embodiments of myinvention:

Fig. 1 is'a front view of a fan embodying my invention;

Fig. 2 is a sideview of'the fan; 4 1

Fig. 3 is a section on the line 3-3; Fig. 2";

Fig.4 is a View of one of the blades as it is molded;

Fig. 5 is an enlarged fragmentary section on the line 5-5, Fig. 1-; I

Fig. 6 is an edge view of the blade shown in Fig; 4 illustrating theblade deformed to the required pitch angle;

Fig. '7 is. a fragmentary View ofa blade showing' a modified form of theinvention;

Fig. 8 is an enlarged section on the line 8-8,

Fig. 7;

Fig. 9 shows a fragmentary sectional view of still a differentembodiment of the invention;

10 is a fragmentary View of a blade illustrating the form of theinvention shown in Fig. 9;

Fig. 11 is a fragmentary view of aportion of thehub showing the slotstherein by which the blade shown in Fig. 10 is secured to the hub.

In the drawing, 1 indicates the hub portion of the fan and 2 are theflexible blades. The hub of thefan is shown as. in the form of a hollowshell member provided with an interior boss 3 adapted to receive the endof the motor shaft or driving shaft 4. In some fans of this type thehollow hub I may form a continuation 55 of a motor housing 40 enclosinga motor, the shaft of which is shown at 4 in dotted lines in Fig. 3. V II I The blades 2', which may have any desirable shape, are preferablymade of rubber or some other suitable flexible material, each blade pre.

senting the outer convexly curved edge 5 and the inner concavely curvededge 6 which ifits.

against the hub portion I and which is referred to as the mountingedgesince it is the edge of theblade which-is mounted on the hub.

The soft rubber or other flexible material of which'the body of theblade is made has not of itself suflicient rigidity to maintain theblade in any predetermined curved shape or at any given pitch angle whenthe fan is in operation, but each blade is. interiorly reinforcedadjacent'its inner edge by a suitable reinforcing member I, which may bea strip ofsheet metal or may be fabric or any other reinforcement whichhas of itself sufficient rigi'dity'to maintain the required curved shapeof and pitch angle to the blade.

This reinforcement is located entirely adjacent the inner or mountingedge 6 of the blade and extends only'a, short distance fromsaid edgethat the greater portion of the blade is nonr'einforce'd and issufficiently flexible so that it will yieldwhen it strikes an object.The blade,

however, has the capacity of resuming its normal shape as soon as thedeforming pressure against the blade has been removed.

nor attaching the blade 13017118 hub, said blade is provided'withtwoattaching ears, one adjacent. each end: thereof, which ears are securedto the h-ub by some suitable means. In Figs. 2

an dB the reinforcingstrip l is formed withtwo I laterally extendingears 8 at the edge 6 of' the blade; These'ears 3 lie against and areriveted or otherwise rigidly secured to the outer face of the hub [asshown at 29.

In making the blade 2,. it is preferably molded to shape in a fiatcondition, the reinforcing strip 1: being molded into the blade. Afterthe blade is molded, then the reinforced blade is deformed or curvedslightly from its leading edge to its trailing edge as shown in Fig. 6,in order to give.

itthe-req1 1ired curved shape and 'pitch angle, and-the reinforcement lis of such character that it will preserve the blade in its deformed'shape and will thus maintain the required pitch angle of the' bla'deindependent of the means whiehtheblade is secured to the hub.

'Eachbl'ade is preferably molded with a con cave mounting edge; as shownin Fig. 5., and hence the blade presents at its base the two flexibleedges 9. These edges project somewhat beyond the inner edge of thereinforcing memberl and beyond the ear 8. As a result, when the blade isattached to the hub by riveting or otherwise securing the ear 8 thereto,these edges 9 of rubber yield laterally and tightly hug the exteriorsurface of the hub I thereby making a preferably tight joint between theinner edge of the blade and said hub.

In Figs. 9 and 10, I have shown a different way of attaching the bladeto the hub. In this embodiment, the reinforcing strip is indicated at Iaand it is formed with two attaching ears or lugs I0, one at each end,which normally lie in the plane of the reinforcing member, and areconnected thereto by a neck portion I2. The hub I is provided with slotsII to receive the lugs I0, the central portion of each slot being ofgreater width than the end portions. In attaching the blade to the hub,the lugs II] are inserted through the slots II, and when the blade ispositioned with its inner edge fitting tightly against the hub, the neckportions I2 of the ears or lugs will be occupying the enlarged portionsof the slots I I. Each ear I is then twisted or turned into a positionextending across its slot, the twist taking place in the necks I2 whichoccupy the enlarged central portions of the slots and which are largeenough to allow for this twisting action, as shown in Figs. 9 and 11.The blades are thus firmly secured to the hub.

In this embodiment of the invention the reinforcement la, has suificientrigidity to maintain the desired curved shape and pitch angle of thesoft rubber blade. The ears I0 and their necks I2 together with theslots II simply serve to position the blade on the hub, but thecurvature of the blade from its leading edge to its trailing edge andthe pitch angle of the blade is maintained by the reinforcing member Ia.

Each blade is at least as thick as the widest dimension of the slots IIand when the blade is in position on the hub, the inner edge 6 thereofcovers and conceals the corresponding slots I I in the hub.

With the construction shown in Figs. 9 to 11, therefore, the means forsecuring the blade to the hub is entirely concealed within the hub, nopart of such securing means being visible on the outside of the hub. Thereinforcing member Ia with its ears I!) may be designated as a mountingmember, since it is the means by which the blade is mounted on the hub.Such mounting member is thinner than the edge of the blade whichcontacts with the hub, said edge of the blade being sufficiently thickor wide to cover the widest portion of the slots II. This concave edgeof the blade which rests against the hub may also be designated as amounting edge.

Another way of attaching the blades to the hub is shown in Figs. 7 and8.

In this embodiment, the attachment is made by means of angular attachingclips I3, one leg I4 of each clip being riveted or secured to the bladeand the other leg I5 of the clip being riveted or otherwise secured tothe hub member I. The interior reinforcement of the blade provides asufficient anchorage for the rivet I6 by which the leg I 4 of the clipis secured to the blade. All embodiments of the invention comprise acomposite hub and blade structure embodying a hollow hub of hardmaterial and a sheet-like blade of relatively soft material having amounting margin terminating in a mounting edge, and a member formounting said blade on said hub comprising a strip of pliant sheet metalhaving a portion of its width bonded to said mounting margin of theblade, and in the embodiment shown in Figs. 9, 10 and 11, the hub orhard material has slots therethrough, and the pliant sheet metal whichis bonded to the mounting margin of the blade has a portion of its widthextending beyond and free from the material of the blade and dividedinto separate bendable sections shaped and disposed to enter the slotsin the hub and to be bent independent- 1y of one another for securingsaid blade to said hub.

Furthermore, in the embodiment shown in Figs. .9, l0 and 11, the pliantsheet metal 1a is thinner than the blade, and the material of the bladeterminates at an edge which flanks the face of the pliant sheet metaland abuts against the exterior surface of the hub, and the projectinglugs I0 by which the blade is secured to the hollow hub are closetedwithin the body of said hub and are thus concealed.

I claim:

1. A flexible-bladed fan having a hub portion, a plurality of separateblades of rubber projecting from the hub portion and each blade havingits inner edge engaging the exterior of the hub, said inner edge of eachblade being concave transversely, and means to secure each blade to thehub with the edges of the concavity pressed against the hub anddeflected laterally, such deflected edges forming a tight joint betweenthe blade and the hub.

2. A flexible bladed fan having a conical hub portion, a plurality ofseparate blades of soft flexible rubber projecting from the hub, eachblade being curved from its leading edge to its trailing edge and havinga concavely curved inner edge which fits and lies against the exteriorof the hub, each blade having two attaching ears, one adjacent theleading edge of the blade and the other adjacent the trailing edge, bywhich the blade is attached to the hub, each blade also being providedalong its inner curved edge with a reinforcing member of sufficientrigidity to maintain the soft rubber blade in its curved form and at therequired pitch angle independently of the means for attaching the bladeto the hub.

3. A flexible bladed fan having a hollow hub portion, a plurality ofseparate blades of soft flexible rub-ber' projecting from the hub, eachblade having a concavely curved inner edge to fit the hub and beingcurved from its leading edge to its trailing edge, means to attach theblade to the hub comprising a pair of slots in the hub for each bladewith each slot having a portion of increased width, and two attachingears extending from the inner edge of each blade, each ear beingconnected to the blade by a neck portion, the ears of each bladeextending through the slots of the corresponding pair of slots and beingtwisted into positions transversely to the slots with the necksoccupying the enlarged portions of the slots, and a reinforcing memberembedded in the rubber of each blade at its inner edge and havingsufllcient rigidity to maintain the soft rubber blade in its curved formand at the desired pitch angle independent of the means for securing theblade to the hub.

4. A flexible bladed fan having a hollow hub portion, a plurality ofseparate blades of soft flexible rubber projecting from the hub, eachblade having a concavely curved inner edge to fit the hub and beingcurved from its leading edge to its trailing edge, means to attach theblade to the hub comprising a pair of slots in the hub for each bladewith each slot having a portion of increased width, and two attachingears extending from the inner edge of each blade, each ear beingconnected to the blade by a neck portion, the ears of each bladeextending through the slots of the corresponding pair of slots and beingtwisted into positions transversely to the slots with the necksoccupying the enlarged portions of the slots, and a reinforcing memberembedded in the rubber of each blade at its inner edge and havingsuflicient rig1dity to maintain the soft rubber blade in its curved formand at the desired pitch angle independent of the means for securing theblade to the hub, the inner edge of each blade overlying and coveringthe corresponding slots in the hub and thus concealing theblade-attaching means.

5. A flexible bladed fan having a hollow hub portion provided withslots, a plurality of separate sheet-like fan blades of relatively softmaterial, each having a mounting margin terminating in a mounting edgewhich is wider than said slots and which engages the exterior surface ofthe hub, and a mounting member for mounting each blade on the hubcomprising a strip of pliant sheet metal thinner than the mounting edgeof the blade and embedded in the blade at its mounting margin, saidmounting member having bendable projecting portions which extend throughthe slots in the hubmember and are bent to extend transversely of theslots, said projecting portions being closeted within the body of thehub, the mounting edge of each blade overlying and covering thecorresponding slots in the hub and thus concealing the bladeattachingmeans.

6. A flexible bladed fan having a hollow hub portion, a plurality ofseparate blades of soft flexible rubber projecting from the hub, eachblade having a concavely curved inner edge to fit the hub and beingcurved from its leading edge to its trailing edge, means to attach theblade to the hub comprising a pair of slots in the hub for each blade,and two attaching ears extending from the inner edge of each blade, theears of each blade extending through the slots of the corresponding pairof slots and being disposed transversely to the slots inside said hollowhub portion, and a reinforcing member embedded in the rubber of eachblade near its inner edge and having sufficient rigidity to maintain thesoft rubber blade in its curved form and at the desired pitch angleindependently of the means for securing the blade to the hub.

7. A flexible bladed fan having a hollow hub portion, a plurality ofseparate blades of soft flexible rubber projecting from the hub, eachblade having a concavely curved inner edge to fit the hub and beingcurved from its leading edge to its trailing edge, means to attach theblade to the hub comprising a pair of slots in the hub for each blade,and two attaching ears extending from the inner edge of each blade, theears of each blade extending through the slots of the corresponding pairof slots and being disposed transversely to the slots inside said hollowhub portion, and a reinforcing member embedded in the rubber of eachblade near its inner edge and having sufficient rigidity to maintain thesoft rubber blade in its curved form and at the desired pitch angleindependently of the means for securing the blade to the hub, the inneredge of each blade overlying and covering the corresponding slots in thehub and thus concealing the blade-attaching means.

8. Concealed structure for mounting an impeller blade of rubber or thelike material in edgewise abutting and upstanding relation to the bodyof an impeller hub, embodying a platelike member thinner than said bladein part embedded within said material, and in part projecting therefrom,and having each of its embedded faces overlapped by a thickness of saidmaterial terminating at an edge flanking the face of the plate-likemember, all of the proj ecting part of said member being closeted withinthe body of said hub and said flanking edge of said rubber or likematerial abutting against the exterior surface of said hub.

9. A composite hub and blade structure embodying in combination with ahub of hard material having slots therethrough, a sheet-like blade ofrelatively soft material having a mounting margin terminating inamounting edge, and a member for mounting said blade on said hubcomprising a strip of pliant sheet metal having a portion of its widthbonded to said mounting margin of the blade, and having a remainingportion of its width extending beyond and free from the material of saidblade and divided into separate bendable sections shaped and disposed toenter said slots in the hub and to be bent independently of one anotherfor securing said blade to said hub.

LOUIS ZAIGER.

